METHOD FOR RENOVATING A RAILWAY LINE

Abstract

 A method for renovating a section of an existing railway line with the removal of a ballast, comprising:
i) a first group of steps comprising the steps of:
- removing rails, sleepers and ballast of a section of the railway line;
- preparing a support layer (10) of said section of the railway line;
- positioning a prefabricated foundation module (21) on said layer (10);
- superposing on said foundation module (21) a prefabricated superstructure plate (81) intended to support one or more rails;
- positioning a temporary stopper (3) in a corresponding seat (810) of the superstructure plate (81); the step of positioning a temporary stopper (3) in a corresponding seat (810) of the superstructure plate (81) being able or not to be part of the step of superposing with said foundation module (21) a prefabricated superstructure plate (81);
- constraining said stopper (3) to the foundation module (21);
- positioning one or more rails (9) on the prefabricated superstructure plate (81) to enable the transit of rolling stock along said section of the railway line;

ii) a second group of steps comprising the steps of:
-removing said temporary stopper (3) from the seat (810);
-creating a bedding layer (5) between the module (21) and the superstructure plate (81); the step of creating the bedding layer (5) comprising the step of introducing by injection a material intended to fill the seat (810) and a space between the foundation module (21) and the superstructure plate (81).

Description

[0001] The subject matter of the present invention is a method for renovating an existing railway line with the removal of the ballast. A railway line also means an underground railway, tram, monorail line, etc.

[0002] In particular, the technical field of the present invention relates to the maintenance and renovation of railway lines in general. In particular, the invention relates to a method that enables a railway line to be restored quickly and effectively, without causing long interruptions on the line itself. Railway lines traditionally envisage a superstructure composed of sleepers, anchoring systems and rails on a ballast.

[0003] More in particular, the superstructure system thus composed is inserted into a ballast, composed of selected particular road metal. The sleepers lie on the latter and by vibration they are buried therein up to the extrados; then the rails are fastened onto them. The sleepers may be made of wood or concrete.

[0004] Maintenance and/or reconstruction work on such type of railway line, which envisages the replacement of the aforesaid traditional type of superstructure with an innovative system without a ballast, actually requires a significant effort especially in terms of interruption time of the railway operations.

[0005] This is because the whole structure described above needs to be dismantled before being rebuilt and, as a new superstructure is to be built without a ballast, the ballast needs to be replaced with a concrete foundation which normally, for ordinary resistance classes, requires long curing times to set and reach the necessary resistance for supporting the loads generated by the subsequent passage of rolling stock.

[0006] For interventions of this type, therefore, the line must be interrupted for a long time, with notable disruptions to traffic.

[0007] A solution of the type described in WO2017/187461 is also known.

[0008] Such solution envisages there being a first micro-step which requires:

• Demolition and removal of the existing portion of binary rail to be replaced;
• Cleaning and preparation of the foundation;
• Laying of foundation plates;
• Creation of connections between foundation plates arranged one after the other;
• Superposition of the binary rail plates with the foundation plates;
• Positioning and fastening of the rails onto the binary rail plates;
• Coring of the foundation plates and insertion of shear reinforcement bars into such cores;
• Temporary alignment and levelling of the binary rail;
• Reactivation of traffic at reduced speed.

[0009] This is followed by a second macro-step that envisages:

• Definitive regulation of the binary rail plates using appropriate set screws;
• Injection of the bedding mortar between the extrados of the foundation plate and the intrados of the binary rail plate with formation of cylindrical stoppers in relevant through holes in the binary rail plates;
• Insertion in relevant compartments of the binary rail plate of special temporary supports that have the task of supporting the load as the railway train sets pass without weighing on the fresh mortar;
• Reactivation of traffic at reduced speed.

[0010] There is then a third macro-step that envisages the dismantling of the temporary works, the performance of the necessary welding and grinding; at the end of this macro-step the traffic can be reactivated at the design speed.

[0011] A drawback of such solution is connected with the transfer of loads, especially tangential loads, between binary rail plates and foundation plates, during the reactivation of the traffic at reduced speed after the first macro-step.

[0012] In this context, the technical task underpinning the present invention is to propose a method for renovating an existing railway line with the removal of a ballast, which enables the interventions to be performed during ordinary traffic interruptions (e.g. at night) optimising safe operation. A further object is that of speeding up the intervention as much as possible.

[0013] The technical task set and the objects specified are substantially attained by a method comprising the technical features as set out in one or more of the appended claims.

[0014] Further features and advantages of the present invention will become more apparent from the approximate and thus non-limiting description of a preferred, but not exclusive, embodiment of a method, as illustrated in the accompanying drawings, in which:

• figures 1 to 9 show a time sequence of a succession of steps of the method according to the present invention;
• figures 10, 11 and 18 show components of an assembly used for the implementation of the method according to the present invention;
• figures 12 to 15 show a detail of some steps of the method according to the present invention;
• figure 16 shows an enlargement of figure 15;
• figure 17 shows a plan view of a portion of figure 16;
• figures 19 and 20 show two views, plan and lateral section, of a component used for the implementation of the method according to the present invention;
• figure 21 shows two orthogonal views of a component used for the implementation of a method according to the present invention;
• figures 22 to 25 show an alternative solution of some steps illustrated in figures 12 to 15;
• figure 26 shows an enlargement of the solution of figure 25;
• figures 27 and 28 show two orthogonal views (including one sectional view) of a detail of figure 25.

[0015] In the appended figures, an assembly for the modification of an existing railway line is indicated, with the removal of a ballast of the line or of a portion thereof.

[0016] It envisages a foundation module 21 (sometimes known as a base plate in technical jargon) and an overlying superstructure plate 81 (sometimes known as a binary rail plate in technical jargon) onto which rails 9 are fastened.

[0017] The foundation module 21 is placed on an infrastructure that can be, according to the case in question: compacted earth, viaduct, bridge or the bottom of a tunnel and on which, as clarified below, the old pre-existing railway structure has been dismantled.

[0018] Other components are however present as clarified in the following description.

[0019] The foundation module 21 is a prefabricated element, preferably made of concrete and, generally, with a rectangular plan shape and with a predetermined height which is also variable.

[0020] Figure 10 shows such foundation module 1 in an axonometric view for describing it better.

[0021] It envisages two short sides parallel to one another and two long sides parallel to one another and so as to have a rectangular plan shape.

[0022] On the side of the two short sides at least two niches 212 are afforded each side. Such niches 212 pass through the entire thickness with a rectangular plan shape. Threaded bars are inserted into such niches 212 for the longitudinal connection of the foundation modules. In the centre of the manufactured element the steel reinforcements exit vertically (in the form of a plurality of bars 213), which were originally inserted into the module 21 during its assembly step.

[0023] Alternatively, such niches 212 may also not be necessarily passing through the entire thickness.

[0024] Therefore, both of the short sides are provided with such niches (preferably rectangular) which face each other perfectly in line when two or more modules are arranged adjacently in succession with one another, as for example highlighted in figure 10.

[0025] The prefabricated module 21 described above can obviously be transported in situ and its indicative dimensions are about 2.60 m for the long side and 2.50 m for the short side. The thickness (therefore the height of the sides) can vary in a range between 20 cm and 30 cm (or 35 cm), as a function of the raised part, preferably about 20 cm. They can therefore be stacked onto one another, can be moved with relevant cranes and transported in situ through relevant railway wagons arranged for such maintenance works on the lines.

[0026] Therefore, various foundation modules are built in an identical way so that, as described below, they can be placed in succession opposite one another so that the niches 212 afforded in the modules themselves coincide in position facing one another (see for example figure 10). Figures 3 and 10 then show a support layer 10 on which the foundation module 21 is placed. It is a bottom layer of concrete with an earthy consistency and will be better described in the description related to the assembly sequence.

[0027] Between the foundation module 21 and the superstructure plate 81 supports 6 are interposed, typically made of resinous material. They may also be made of elastomer, as long as they perform a temporary support action. They must have specific elastic characteristics. The supports 6 are temporary. They have the role of supporting the vertical loads temporarily to enable the transit of rolling stock. They will later be removed and replaced with the definitive cast of cementitious mortar. Typically the supports 6 are shaped like strips.

[0028] On the upper surface of the foundation module 21 (preferably at the position of the rail) compartments are obtained for the insertion of the temporary supports 6. The aforesaid compartments prevent the elastic support 6 from moving during the passage of the rolling stock.

[0029] As exemplified in the sections of figures 5, 14, 16, the assembly of the overlying superstructure plate 81 is envisaged (also known as the binary rail plate in technical jargon). It is of the precompressed type, typically PRC.

[0030] The superstructure plate 81 is reinforced and precompressed along the two main directions in order to make it resistant to stress actions and fatigue phenomena, removing cracks under working conditions and making the element durable over time. Generally, the useful life of the structural elements of the system is fixed at a minimum of fifty but estimated to be around sixty years and more. Rails and plastic or elastomeric elements have a much shorter useful life and, therefore, replacement times will follow depending on the wear due to the loads and frequency of the railway operations.

[0031] The precompression procedures and techniques are per se well known in the state of the art and in the specific case of the railway platform harmonic steel strands or wires will be used with pre- or post-compression. Figure 11 depicts an axonometric view of the precompressed superstructure plate 81. It is also a transportable manufactured element. Such superstructure plate 81, as shown in figure 11, comprises a plurality of supports 811 for the attachments of the rail. Such supports 811 are a single body with the platform and the attachment members are fastened onto such supports, as mentioned, onto which the rails 9 are then positioned and fastened.

[0032] On the superstructure plate 81 the supports 811 may be for a type of attachment made by the company Vossloh, but also for any other supplier. In the event of using other types of attachment, e.g. Pandrol FCB, they could for example require a flat surface or a different conformation of the supports 811.

[0033] Therefore, definitively, it is the superstructure plate 81 that adapts in its conformation to the envisaged attachment, therefore being able to envisage both a different number and type of attachments.

[0034] Figures 14 and 15 show the superstructure plate 81 on which the rails 9 are already mounted but it is to be understood that it is obviously manufactured without rails which are mounted subsequently during the step of mounting and restoring the line.

[0035] The appended figures illustrate a standard connection system well known for connecting the rails 9 to such supports 811, with a system known by the commercial name of "Vossloh 300 attachment" but, as mentioned above, other equivalent systems could also be used (e.g. "Pandrol FCB attachment).

[0036] As exemplified in figure 11, the superstructure plate 81 has at least one, preferably at least two, through holes 810 which, with the injection of mortar, create two definitive stoppers and which, as clarified below, enable the pressurised injection or injection by gravity of the bedding mortar. Sometimes there may be more than two of such through holes 810.

[0037] The section of figure 8 shows the layer of bedding mortar 5 which fills the space between the foundation module 21 and the superstructure plate 81. The section of figure 16 further highlights such hole 810 and shows the anchoring bars 213 that are appropriately located inside such hole 810. Such bars 213 are incorporated into the underlying foundation module 21 and are completed with brackets, as clarified below, before the definitive bedding mortar injection.

[0038] Figures 16, 19, 20 show the temporary stopper 3 that has the task of transferring the longitudinal and lateral actions due to the passage of rolling stock at reduced speed, before being replaced by the definitive stopper. The temporary stopper 3 comprises/is a cylinder (typically metal, in particular steel) which is fastened to the construction joint bars 213 present in the foundation module 21. To enable the regulation of the superstructure plates, the temporary stopper 3 has a smaller diameter than that of the housing 810 into which it is inserted. Therefore, so that it is effective, once installed, the remaining space must be filled with a material that enables safe fastening and contact. For that purpose, between the stopper 3 and the superstructure plate 81, a ring of resin 4 is inserted which, once hardened, temporarily transfers the loads between the superstructure plate 81 and the foundation module 21 until it is replaced by the definitive stopper.

[0039] Regulation systems 85 are also provided so as to place the binary rail 9 in the correct geometry from the planimetric/altimetric point of view.

[0040] Such regulation systems 85 are clearly visible in the view of figure 14. They comprise, for example, bolts on which to act by screwing or unscrewing with the consequent lifting or lowering of the binary rail until it reaches the correct position.

[0041] More in particular, figure 14 shows a threaded shank 89 of the bolt inserted into a channel 87 passing through the superstructure plate 81 and into which a nut 880 is buried in the prefabrication step, so that when the shank 89 is inserted into the channel 87 it is screwed to the nut 880 and, continuing to screw, it exits from the opposite side and creates a support (coming into contact with the foundation module 21). In this way, according to the rotation direction that is imparted to the shank 89 an advancement of the shank 89 itself with respect to the nut 880 is generated, causing the lifting/lowering of the superstructure plate 81. If, for example, the right hand shank 89 of figure 14 is left in the position shown and only the left hand shank 89 is acted upon, it is possible to tilt the entire superstructure plate 81 with the overlying structure on one side.

[0042] Preferably, a plurality of bolts are provided (preferably four) for regulating the superstructure plate 81 provided on one side and on the opposite side in a symmetrical way.

[0043] The system for fastening the rails 9 onto the supports 811 can be adapted for the insertion of the most common attachment members on the market and chosen as a function of the specific relevant requirements.

[0044] The subject matter of the present invention is a method for modifying (renovation in technical jargon) of an existing railway line with the removal of a ballast. It is specified that a ballast means the layer of gravel or ballast in which the sleepers lie.

[0045] Such method comprises a first group of steps (or even first macro-step). Advantageously the first macro-step is performed during an ordinary interruption of the traffic along the railway line (e.g. during the night-time when the traffic stops). Such first group of steps comprise a step for the removal of the rails, sleepers and ballast of the existing railway line. This is exemplified by the passage from the configuration of figure 1 to that of figure 2.

[0046] Preliminarily, the rails are to be cut. Furthermore, with excavators and/or railway wagons and/or mechanical tools in general the rails, the sleepers and the ballast are removed in this order.

[0047] Prior to such operation, the traffic along the railway line has necessarily been suspended.

[0048] Appropriately, the first group of steps can comprise a step of creating a support layer 10 for supporting the railway line (the new one). Such layer 10 in technical jargon is also called a levelling layer (as it enables a predefined level to be reached). This takes place subsequently to the demolition of the existing binary rail. This step can comprise the sub-step of modifying an existing foundation, bringing the ground to a pre-defined level through excavation or backfill and then levelling and compacting it. This takes place for example with the use of excavators and vibrocompactors.

[0049] Appropriately, a topographic survey can be performed on the levels of the foundation.

[0050] The step of preparing the layer 10 also comprises the creation of a bedding cast (typically made of concrete), see for example figure 3.

[0051] The concrete must have the consistency of so-called wet earth. Appropriately it has a minimum thickness of about 8 - 10 cm. The concrete casts (or similar material) can possibly be performed with pumps and pipes that can even be at a distance (e.g. 150 - 200 metres), appropriately on railway wagons placed on the binary rail.

[0052] Such layer 10 can therefore be defined as a foundation bedding cast.

[0053] The method further comprises the step of positioning a plurality of prefabricated foundation modules on said layer 10. Such foundation modules are placed consecutively one on top of the other along the railway line 1 (as shown for example in figure 10). Appropriately such step comprises positioning a prefabricated foundation module 21 (appropriately on said layer 10; appropriately it is placed directly in contact, but the presence of an intermediate element cannot be excluded a priori). See figure 3 for this purpose.

[0054] Advantageously, this takes place with the use of tracked carriers, or with mobile cranes, which collect the foundation modules from railway wagons and then rest them on the layer 10.

[0055] Appropriately, the step of positioning a plurality of foundation modules comprises the step of resting the foundation modules in sequence one opposite the other. The step of positioning a plurality of prefabricated foundation modules on said base 10 comprises a step of positioning a further foundation module 22 (which can therefore be defined as the second module) consecutively to the foundation module 21 (which can therefore be defined as the first module 21). Typically the laying tolerance is in the order of 2-3 cm. Therefore, the foundation modules together define a longitudinal strip. Such strip (orthogonally to the axis of the rail) has a width for example comprised between 2.4 and 2.6 metres.

[0056] Appropriately the first and the second foundation modules 21, 22 comprise, respectively, a first and a second connector 211, 221. Appropriately, the first and the second connector 211, 221 can be connected to one another. In a particular solution this takes place by screwing (however, it could take place in another way, e.g. via quick connection or guillotine joints, etc.). For example, the first connector 211 could comprise a first longitudinal extension element. The second connector 221 can for example comprise a second threaded longitudinal element and a sleeve that can be screwed both onto the first and the second longitudinal element for connecting them together.

[0057] In the preferred solution the first and the second connector 211, 221 are at least partially housed respectively in a first and a second niche 210, 220 obtained one on the first and one on the second module 21, 22. In particular, the first and the second connector 211, 221 are partially buried respectively in the first and the second foundation module 21, 22.

[0058] The step of positioning the second foundation module 22 consecutively to the first foundation module 21 takes place by placing the first and the second niche 210, 220 opposite one another. Typically there is a plurality of niches (with corresponding connectors) along two sides of the first and the second foundation module 21, 22 which are placed opposite one another.

[0059] Appropriately, the method comprises the step of positioning at least one temporary elastic support 6 on the foundation module 21. Appropriately, this takes place once the laying of the foundation modules has been completed and the connection between them has been made. Advantageously, this envisages inserting such elastic support 6 into a break 60 in the extrados (upper face) of the module 21. The step of positioning the elastic support 6 on the module 21 can take place in the work site or the elastic support 6 can be preassembled (see again figure 4), typically in the factory. Appropriately, such elastic support 6 projects externally to said recess 60. Appropriately, such elastic support 6 is shaped like a strip. Advantageously, such strip is arranged so as to have the long side parallel to the direction along which the axis of the rail is intended to extend. Appropriately, a plurality of distinct elastic supports 6 (advantageously elastomer portions) are positioned on the foundation module 21. They are advantageously shaped like strips. Advantageously, they are inserted into corresponding breaks 60 afforded on the extrados of the module 21 (see for example figure 10). Appropriately, the elastic support 6 to which reference is made herein could be elastomeric. Appropriately, it acts as a bearing (typically between the module 21 and the superstructure plate 81 described below). The elastic support 6 therefore remains interposed between the foundation module 21 and the superstructure plate 81.

[0060] The method further comprises the step of superposing on said foundation module a prefabricated superstructure plate intended to support one or more rails.

[0061] In particular, the method comprises the step of superposing on the foundation module 21 a prefabricated superstructure plate 81 intended to support said one or more rails 9 (see figure 5). This enables the passage of rolling stock on said rails 9.

[0062] The method further comprises the step of temporarily positioning a temporary stopper 3 in a corresponding seat 810 of the superstructure plate 81. The step of positioning the stopper 3 and the adjacent elements is better highlighted in the succession of figures 12-15. The step of temporarily positioning a stopper 3 in a corresponding seat 810 of the superstructure plate 81 can be part of the step of superposing a prefabricated superstructure plate 81 on said foundation module 21. This for example envisages that the insertion of the stopper 3 in said seat 810 takes place as a result of the superposition of the superstructure plate 81 on the foundation module 21, said stopper 3 being first placed on the foundation module 21.

[0063] In an alternative not preferred solution the stopper 3 could be inserted into said seat 810 after the step of superposing the superstructure plate 81 on said module 21.

[0064] Appropriately, the method comprises the step of positioning at least said elastic support 6 between the foundation module 21 and the superstructure plate 81. Advantageously, this is obtained with the step of superposing a prefabricated superstructure plate 81 on the foundation module 21. In fact, in this way the elastic support 6 previously resting on the foundation module 21 remains interposed.

[0065] The method further comprises the step of constraining the stopper 3 to the foundation module 21 for transferring the tangential stress between the superstructure plate 81 and the foundation module 21. This advantageously takes place by connecting the stopper 3 to bars 213 constrained to the module 21 (e.g. buried or constrained by means of a stop 215). For example, threaded elements 214 can be screwed to said bars 213, trapping a portion of said stopper 3.

[0066] The first group of steps can also comprise the step of positioning at least one insert 40 in said seat 810, placing it between the stopper 3 and said prefabricated superstructure plate 81 (see figure 15). Such insert 40 enables any lateral play between the stopper 3 and the seat 810 to be minimised therefore any vibrations/oscillations upon the passage of railway train sets.

[0067] Appropriately, said insert 40 comprises a hardening means 4.

[0068] The step of activating the hardening of said hardening means 4 is appropriately envisaged. Said at least one insert 40 is introduced between the stopper 3 and the superstructure plate 81 in a state in which the hardening means 4 is still mouldable and/or flexible and hardens or completes its hardening when it is in the position between the stopper 3 and the superstructure plate 81.

[0069] Preferably, said at least one insert 40 comprises a flexible casing 400 (appropriately a jacket), e.g. made of plastic. Such casing 400 is appropriately toroidal. Appropriately, the casing 400 contains the hardening means 4 which, for example, comprises a fluid epoxy resin. The step of activating the hardening of the hardening means 4 comprises the step of introducing a chemical reactant into the casing 400, appropriately through an injection valve. Appropriately such flexible casing 400 can be positioned annularly around the stopper 3. This enables the empty space which remains in the hole 810 between the stopper 3 and the superstructure plate 81 to be filled.

[0070] The step of positioning said at least one insert 40 in said seat 810 comprises the step of positioning said at least one insert 40 (appropriately containing the hardening means) around said stopper 3. For example, said jacket may be annular (e.g. torus shaped) or a longitudinal body that can be bent to assume an annular conformation. In a further alternative solution said at least one insert 40 could comprise a plurality of pieces (preferably prismatic) which are arranged around the stopper 3 along an annular path.

[0071] Appropriately, the step of positioning said at least one insert 40 in said seat 810 is preceded by the step of positioning in said seat 810 a base for the support 30 of said at least one insert 40 (see for example figure 14). For example, such base 30 may be an annular element, preferably flexible, e.g. made of foam rubber. Possibly, such support base 30 could be integrated into the stopper 3, but is preferably a body constrained by the stopper 3. The base 30 prevents the stopper 3 from being able to fall below the platform 81. The support base 30 therefore defines a lower support of the stopper 3. It facilitates the stable positioning thereof in the seat 810. In an alternative solution, such support base 30 could even be omitted.

[0072] Advantageously, the method comprises the step of applying an upper retaining means 300 of said at least one insert 40 in said seat 810. The upper retaining means 300 comprises for example a clamp (see figures 16, 17, 21). The means 300 can be fastened (typically in a removable way) to the stopper 3. The means 300 enables said at least one insert 40 to be constrained at the top.

[0073] Appropriately, in an alternative solution illustrated in figures 22-25, the method of positioning a temporary stopper 3 in said seat 810 comprises positioning in said seat 810 a stopper 3 having a lateral surface intended to come into contact with a wall that delimits said seat 810. A lateral surface of the stopper 3 could therefore comprise a coating 301, typically annular, for example made of neoprene (such stopper 3 is exemplified in figures 26-28). For example, the lateral surface of the stopper 3 could be substantially countershaped to said seat 810. Advantageously, the superstructure plate 81 could be positioned on the foundation module 21 already with the stopper 3 integrated. The play between the lateral surface of the stopper 3 and the seat 810 is minimal. Therefore, it is not necessary to introduce an insert 40 to compensate the radial play and minimise vibrations upon the passage of a railway train set. Appropriately, such temporary stopper 3 is fixed to the foundation module 21, typically to the bars 213. This can take place by means of at least one stop 214, for example one or more bolts that are applied to the bars 213. This happens from above, e.g. through a top opening of the stopper 3 which enables the stopper 3 to be fixed to the bars 214. Appropriately, on this point said stop 302 can be used to compress the stopper 3 against the underlying foundation module 21.

[0074] The method (in particular the first group of steps) comprises the step of performing a planimetric/altimetric regulation of the superstructure plate 81 (see for example figure 5 and figure 14). On this point, there is a plurality of spacer elements 85 that enable the distance of corresponding points of the superstructure plate 81 to be regulated from underlying points of the foundation module 21. Advantageously, such spacer elements 85 comprise threaded elements comprising a shank 89 that crosses the superstructure plate 81. The shank 89 can be screwed onto a nut 880 buried inside the superstructure plate 81 during the manufacturing step. As a function of the degree of screwing such shank 89 projects to a greater or lesser extent below said superstructure plate 81 (coming into contact with the foundation module 21). Therefore two superposed points of the superstructure plate 81 and of the foundation module 21 can be distanced. By acting on a plurality of such spacer elements 85 (preferably four), distributed in various points of the superstructure plate 81 it is possible to regulate not only the distance between the superstructure plate 81 and the foundation module 21, but also the planarity of the superstructure plate 81.

[0075] The method also comprises the step of positioning said one or more rails 9 on the prefabricated superstructure plate 81 to enable the transit of rolling stock at reduced speed along the railway line 1 (see figure 6).

[0076] Appropriately, the step of performing said planimetric/altimetric regulation takes place prior to the step of positioning said one or more rails. Possibly, it could take place or be repeated at a later date, but however prior to the step (described below) of creating the bedding layer 5.

[0077] Preferably, the first group of steps (depicted from figure 1 to figure 6) takes place during a first interruption of the rolling stock traffic along the railway line 1. Typically, such first interruption is at night-time. In fact, in the night-time hours the railway traffic is less frequent and in many portions completely suspended. Therefore, it does not penalise normal traffic.

[0078] The method according to the present invention also comprises a second group of steps (that can also be defined as the second macro-step). The second group of steps (depicted from figure 7 to figure 9) takes place during a second interruption of the rolling stock traffic along the railway line 1. The second group of steps takes place after at least 4 hours (preferably 8 hours) from the first interruption. Appropriately also the second interruption is at night-time. Typically it takes place the night after the first interruption. Such second group of steps in turn comprises the step of creating a bedding layer 5 between the module 21 and the superstructure plate 81 (see figure 8). The step of creating the bedding layer 5 appropriately comprises the step of introducing (typically by injection) a material intended to harden between the module 21 and the superstructure plate 81. Such material is typically a hydraulic mortar. Appropriately, the step of creating a bedding layer 5 comprises the step of making a formwork 90 around a gap between the module 21 and the superstructure plate 81 (see figure 7). In this way the formwork 90 enables the introduction of such material intended to harden to be confined to a confined space. Appropriately, the step of making the formwork 90 follows the step of removing said elastic support 6 between the module 21 and the superstructure plate 81.

[0079] Preferably the second group of steps comprises the step of removing said elastic support 6 before creating said bedding layer 5. In particular, all the elastomeric strips introduced into the corresponding breaks 60 and placed to support the superstructure plate 81 are removed.

[0080] Advantageously, the second group of steps comprises the step of removing said temporary stopper 3 and said possible at least one insert 40 before creating said bedding layer 5 between the module 21 and the superstructure plate 81.

[0081] The method comprises introducing into the seat 810 after the removal of the stopper 3, a material that by hardening defines a definitive stopper. This can take place as described below. The step of introducing by injection a material intended to harden between the module 21 and the superstructure plate 81 appropriately envisages occupying (preferably completely filling) also said seat 810 with the material used for the bedding layer 5. The step of introducing said material between the module 21 and the superstructure plate 81 preferably takes place through the seat 810 or one or more injection holes especially arranged in the prefabricated element.

[0082] Appropriately, the method also comprises a third group of steps (that can also be defined as a third macro-step). The third group of steps can in turn comprise finishing works, e.g. removal of the formwork 90 for containing the bedding mortar and/or the possible adaptation of the water drainage system, filling with gravel or ballasts or with walkable prefabricated elements to the sides of the binary rail.

[0083] The third group of steps can comprise a step of welding and/or grinding. Therefore, the traffic can be reactivated at the design speed. The third group of steps takes place during a further interruption of the railway traffic, which typically takes place during the night after the one in which the second macro-step was performed.

[0084] To summarise, in the preferred solution, the method comprises the following steps:

• from figure 1 to figure 2: removal of ballasts, sleepers, binary rails and cleaning of the base;
• figure 3: regularisation of the base by laying lean concrete with the consistency of wet earth and curing of concrete also checking the level of the extrados;
• figure 4: laying of prefabricated foundation modules with temporary metal stopper elements constrained to the anchor bolts arranged on the extrados of the foundation; on the foundation modules, elastic supports are provided, or laid, which are intended for the vertical support of plates described in the following point.
• figure 5: laying of prefabricated plates with attachment member for premounted binary rail;
• figure 6: laying and fastening of the rails, checking the geometry of the binary rail (preferably with a topographic carriage), planimetric/altimetric adjustment, temporary fastening of stoppers (as illustrated more clearly in figures 13-15); it is possible to restart the railway traffic at reduced speed;
• figure 7: removal of elastic supports, checking the binary rail geometry and final adjustment, positioning of formworks for injection;
• figure 8: injection of bedding mortar;
• figure 9: completion of the construction of the binary rail without ballast; it is possible to restart the railway traffic at reduced speed.

[0085] Then the finishing works are performed (as described in the third macro-step that enable the reopening of the railway traffic at the design speed). The present invention achieves important advantages.

[0086] Above all, it enables an existing railway line to be modified with the removal of the ballast extremely quickly and enabling the maintenance interventions to be split up into different times, in the meantime enabling the traffic to continue at reduced speed. A further important advantage is connected with the fact that it enables such traffic at reduced speed in absolutely safe conditions.

[0087] The invention as it is conceived is susceptible to numerous modifications and variants, all falling within the scope of the inventive concept characterised thereby. Furthermore, all the details can be replaced with other technically equivalent elements. In practice, all the materials used, as well as the dimensions, can be any whatsoever, according to need.

Claims

1. A method for renovating a section of an existing railway line with the removal of a ballast, comprising:

i) a first group of steps comprising the steps of:

- removing rails, sleepers and ballast of a section of the railway line;

- preparing a support layer (10) of said section of the railway line;

- positioning a prefabricated foundation module (21) on said support layer (10);

- superposing on said foundation module (21) a prefabricated superstructure plate (81) intended to support one or more rails;

- positioning a temporary stopper (3) in a corresponding seat (810) of the superstructure plate (81); the step of positioning a temporary stopper (3) in a corresponding seat (810) of the superstructure plate (81) being able or not to be part of the step of superposing with said foundation module (21) a prefabricated superstructure plate (81);

- constraining said stopper (3) to the foundation module (21);

- positioning one or more rails (9) on the prefabricated superstructure plate (81) to enable the transit of rolling stock along said section of the railway line;

ii) a second group of steps comprising the steps of:

- removing said temporary stopper (3) from the seat (810);

- creating a bedding layer (5) between the module (21) and the superstructure plate (81); the step of creating the bedding layer (5) comprising the step of introducing by injection a material intended to fill a space between the foundation module (21) and the superstructure plate (81); the step of introducing said material by injection envisages also occupying said seat (810) with the material used for the bedding layer (5).

2. The method according to claim 1, characterised in that the first group of steps comprises the step of positioning at least one insert (40) in said seat (810), placing it between the stopper (3) and said prefabricated superstructure plate (81).

3. The method according to claim 2, characterized in that said insert (40) comprises a hardening means (4).

4. The method according to claim 3, characterised in that the first group of steps comprises a step of activating a hardening of said hardening means (4) so that said hardening means (4) is introduced between the stopper (3) and the superstructure plate (81) in a state in which it is still flexible and hardens or completes its hardening when it is in position between the stopper (3) and the superstructure plate (81).

5. The method according to claim 4, characterised in that the step of activating a hardening of said hardening means (4) comprises a step of introducing a chemical reactant into a flexible casing (400) containing a substance intended to react with said chemical hardening reactant; said casing (400) being part of said insert (40).

6. The method according to any one of the preceding claims, characterised in that the step of positioning said at least one insert (40) in said seat (810) comprises the step of positioning an annular insert (40) around said stopper (3).

7. The method according to any one of the preceding claims, characterised in that the first group of steps takes place during a first interruption of the railway traffic along the railway line (1); the second group of steps taking place during the second interruption of the railway traffic along the railway line (1).

8. The method according to claim 7, characterised in that said second group of steps starts at least 8 hours after the first interruption.

9. The method according to any one of the preceding claims, characterised in that the first group of steps comprises the step of positioning at least one elastic support (6) between the foundation module (21) and the superstructure plate (81).

10. The method according to claim 9, characterised in that the second group of steps comprises the step of removing said elastic support (6) before creating said bedding layer (5).

11. The method according to any one of the preceding claims, characterised in that it comprises a step of positioning, consecutively to the foundation module (21), a further foundation module (22) connecting them by means of connectors (211, 221).

Drawing